Cost-effectiveness of sponge cytology test vs endoscopy for esophageal squamous cell carcinoma screening in high-risk areas

Table 1 Model input

Parameter	Base case	Range1	Distribution2	Ref.
Prevalence (%)3				Zeng et al[14], 2020; Xia et al[18], 2021; Chen et al[37], 2017; and Xia et al[38], 2022
mD	2.04	1.02-4.52	Triangular (0.0102, 0.0204, 0.0452)
MD	0.22	0.11-0.59	Triangular (0.0011, 0.0022, 0.0059)
SD/CIS	0.12	0.06-0.38	Triangular (0.0006, 0.0012, 0.0038)
EEC	0.05	0.03-0.10	Triangular (0.0003, 0.0005, 0.0010)
AEC	0.02	0.01-0.04	Triangular (0.0001, 0.0002, 0.0004)
Annual state transition rate4				Xia et al[18], 2021; Chen et al[37], 2017; and Xia et al[38], 2022
Healthy to mD	0.0120	± 50%	Triangular (0.006, 0.012, 0.018)
mD to healthy	0.0500	± 50%	Triangular (0.025, 0.05, 0.075)
mD to MD	0.0500	± 50%	Triangular (0.025, 0.05, 0.075)
MD to mD	0.0800	± 50%	Triangular (0.04, 0.08, 0.12)
MD to SD/CIS	0.1200	± 50%	Triangular (0.06, 0.12, 0.18)
SD/CIS to MD	Age-specific
SD/CIS to EEC
EEC to AEC
PT-SD/CIS to SD/CIS	0.0050	± 50%	Triangular (0.0025, 0.005, 0.0075)
PT-EEC to EEC	0.0500	± 50%	Triangular (0.025, 0.05, 0.075)
PT-EEC to AEC	0.1000	± 50%	Triangular (0.05, 0.10, 0.15)
PT-AEC to AEC	0.2304	± 50%	Triangular (0.115, 0.23, 0.345)
Participation rate				Gao et al[8], 2023; Xia et al[18], 2021; Chen et al[37], 2017; and Xia et al[38], 2022
Endoscopy screening	0.3352	± 50%	Triangular (0.30, 0.34, 0.67)
Sponge cytology screening	0.56	± 50%	Triangular (0.50, 0.56, 0.80)
Endoscopy after sponge cytology test	0.75	± 50%	Triangular (0.40, 0.75, 0.90)
Probability of receiving treatment3				Xia et al[18], 2021; Chen et al[37], 2017; and Xia et al[38], 2022
SD/CI	0.7458	0.5625-0.9654	Beta (20.75, 7.07)
EEC	0.9405	0.7149-1.0000	Beta (5.13, 0.32)
AEC	0.9643	0.8393-1.0000	Beta (11.08, 0.41)
Probability of symptomatic detection				Xia et al[18], 2021; Chen et al[37], 2017; and Xia et al[38], 2022
SD/CIS	0.01	0.005-0.02	Triangular (0.005, 0.01, 0.02)
EEC	0.20	0.10-0.40	Triangular (0.10, 0.20, 0.40)
AEC	0.70	0.56-0.90	Triangular (0.56, 0.70, 0.90)
Cost (USD)
Endoscopic test	74.31	± 50%	Triangular (50.36, 74.31, 108.69)	Xia et al[18], 2021; Li et al[19], 2019; Chen et al[37], 2017; and Xia et al[38], 2022
Sponge cytology test	35	± 50%	Triangular (17.5, 35, 52.5)	Estimated
Endoscopic complications	119.61	± 50%	Gamma (9.75, 0.08)	Xia et al[18], 2021; Chen et al[37], 2017; and Xia et al[38], 2022
Initial treatment				Xia et al[18], 2021; Chen et al[37], 2017; and Xia et al[38], 2022
SD/CIS	1687.61	± 50%	Gamma (3.33, 0.002)
EEC	8135.03	± 50%	Gamma (2.33, 0.0003)
AEC	7701.55	± 50%	Gamma (0.03, 0.00004)
Annual treatment
SD/CIS	227.26	± 50%	Gamma (1.27, 0.006)
EEC	386.13	± 50%	Gamma (1.23, 0.003)
AEC	359.83	± 50%	Gamma (2.05, 0.006)
Characteristics of tests
Sensitivity of endoscopy	100%	0.88-1	-	Xia et al[18], 2021; Nagami et al[39], 2014; and Dawsey et al[40], 1998
Specificity of endoscopy	100%	0.59-1	-
Sensitivity of sponge cytology test	94.5%	0.888-0.975	Triangular (0.888, 0.945, 0.975)	Gao et al[8], 2023
Specificity of sponge cytology test	91.9%	0.912-0.925	Triangular (0.912, 0.919, 0.925)
Complication rate of endoscopic test	0.00023	0-0.002	Triangular (0, 0.00023, 0.0013)	Silvis et al[41], 1976 and Wang et al[42], 2019
Health state5				Xia et al[18], 2021 and Liu et al[20], 2018
mD	1	0.98-1	Triangular (0.98, 1.00, 1.00)
MD	1	0.98-1	Triangular (0.98, 1.00, 1.00)
SD/CIS	0.84	0.79-0.89	Beta (3.57, 0.68)
EEC	0.70	0.66-0.74	Beta (2.63, 1.13)
AEC	0.61	0.56-0.66	Beta (1.12, 0.71)
PT-SD/CIS	0.90	0.88-0.92	Beta (2.26, 0.25)
PT-EEC	0.81	0.79-0.83	Beta (1.77, 0.41)
PT-AEC	0.74	0.71-0.77	Beta (0.95, 0.33)
Discount rate	0.05	0-0.08		Liu et al[21], 2022

¹Upper and lower limits of parameters were determined based on a 95% confidence interval, a 50% range, or a range of estimates[22,43].

²Utilities were assigned a beta distribution, and costs were assigned a gamma distribution. A triangular distribution encompassed the range between the minimum.

³Baseline proportion of individuals in each disease state at model entry.

⁴Annual probabilities of moving between health states.

⁵Utilities scores: Quality-of-life weights for quality-adjusted life year. calculation; 0 = death, 1 = perfect health.

mD: Mild dysplasia; MD: Moderate dysplasia; SD/CIS: Severe dysplasia/carcinoma in situ; EEC: Early esophageal cancer; AEC: Advanced esophageal cancer; PT: Post-treatment.

Table 2 Base case: Health outcomes

Strategy	Health outcomes (per 100000 participants)
	ESCC cases	ESCC deaths
No screening	3134	2409
Sponge cytology screening
Once	2962	2266
Every 10 years	2515	1874
Every 5 years	2011	1469
Every 3 years	1510	1088
Every 2 years	1060	750
Every year	373	257
Endoscopic screening
Once	2943	2305
Every 10 years	2606	2006
Every 5 years	2277	1685
Every 3 years	1867	1362
Every 2 years	1470	1052
Every year	755	514

Health outcomes are presented per 100000 participants for each screening strategy. ESCC: Esophageal squamous cell carcinoma.

Table 3 Base case: Cost-effectiveness outcomes

Strategy	Cost per 100000 participants (USD)	QALYs per 100000 participants	Incremental cost per 100000 participants (USD)		QALYs gained per 100000 participants		ICERs (USD per QALY gained)
			Against no screening strategy	Among all strategies	Against no screening strategy	Among all strategies	Against no screening strategy	Among all strategies
No screening	4532190	1473925	-	-	-	-	-	-
Sponge cytology screening
Once	6452020	1474672	1919830	1919830	747	747	2571	2571
Every 10 years	8691075	1475723	4158885	4158885	1798	1798	2313	2313
Every 5 years	11823542	1476865	7291352	3132467	2940	1142	2480	2743
Every 3 years	15682730	1478055	11150540	3859188	4129	1190	2700	3244
Every 2 years	20115833	1479177	15583643	4433104	5252	1122	2967	3950
Every year	32781384	1481087	28249194	12665550	7162	1910	3944	6630
Endoscopic screening
Once	7019587	1474458	2487397	567568	532	-214	4671	Dominated
Every 10 years	9716978	1475250	5184788	1025903	1324	-473	3915	Dominated
Every 5 years	13676309	1476120	9144119	185767	2194	-745	4167	Dominated
Every 3 years	18773932	1477073	1424742	3091202	3147	-982	4525	Dominated
Every 2 years	24851313	1478033	20319123	4735480	4108	-1144	4946	Dominated
Every year	42263921	1479898	37731731	9482537	5972	-1189	6318	Dominated

Dominated, negative incremental cost-effective ratios are regarded as dominated. Costs and quality-adjusted life years are reported per 100000 participants for each screening strategy. QALY: Quality-adjusted life year; ICER: Incremental cost-effective ratio.